CVE-2026-76187
No allowlist restricts which client ids may authenticate, so the credentials of an unrelated application that happens to share the realm are valid Airflow login credentials, and Airflow mints a signed session token for that application's service account.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.95%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
Apache Airflow Keycloak provider: the unauthenticated token endpoint accepts a client-credentials grant for any confidential client registered in the Keycloak realm, not only the client configured for Airflow. No allowlist restricts which client ids may authenticate, so the credentials of an unrelated application that happens to share the realm are valid Airflow login credentials, and Airflow mints a signed session token for that application's service account. The endpoint also answers unauthenticated credential guesses against Keycloak under Airflow's identity. Affects deployments using the Keycloak auth manager whose realm is shared with other confidential clients. The attacker needs valid credentials for any one of those clients, not for Airflow. Resource authorization is still evaluated per subject, so the access gained is whatever that service account holds, plus any endpoint gated only on being authenticated. Users of apache-airflow-providers-keycloak are recommended to upgrade to version 0.10.0 or later, which accepts only the configured client on that grant.
- CVSS 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.95% probability · 60th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-287
- Affected
- apache/apache-airflow-providers-keycloak
- Source
- security@apache.org
EPSS 0.9% since 19 September 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://github.com/apache/airflow/pull/72205Patch, Vendor Advisory
- https://lists.apache.org/thread/5cqh5ojl3718ogb0q1dcd9vdr47z7gp3Mailing List
- https://lists.apache.org/thread/j1b9ddljxphqvoc41z7gthj4zh34vmlw?users@airflow.apache.orgMailing List
- http://www.openwall.com/lists/oss-security/2026/09/15/9Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.